The present invention relates to a power steering apparatus and a method of manufacturing a power steering apparatus.
A technique relating to power steering apparatus is disclosed in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2008-509353. The JP Publication discloses a ball bearing helical gear mechanism transmitting an output from an electric motor to a spindle.
According to the technique disclosed in the above-described JP Publication No. 2008-509353, a nut of the ball bearing helical gear mechanism has projections and recesses on the outer periphery thereof. Accordingly, to form the nut by die forging, a die used for the die forging process has to be released in the radial direction of the nut because of the presence of the projections and recesses, and it is necessary to form the hollow portion of the nut by cutting, resulting in a reduction in the yield.